Part 3
Automatic Transmission
Power Flow 3rd Gear
The gear selector lever and the manual selector spool valve are in the 'D' position. Engine torque is transmitted from the torque converter turbine shaft to the ring gear 1 of the single web planetary gear train and the outer plate carrier of clutch 'E'.
Ring gear 1 drives the planetary gears which rotate around sunwheel 1. This drives the planetary gear carrier 1 and also the outer plate carrier of clutch 'A' and the inner plate carrier of clutch 'B'.
When clutch 'A' is engaged, sunwheel 3 in the double web planetary gear train is driven and meshes with the short planetary gears.
Sunwheel 2 is driven via clutch 'B' which is engaged. The long planetary gears, which are also meshed with the short planetary gears, cannot roll around the fixed sunwheel 2 and transmit drive to the locked double web planetary gear train carrier in the direction of engine rotation.
NOTE:
Refer to 'Shift Elements' illustration for key
Power Flow 4th Gear
The gear selector lever and the manual selector spool valve are in the 'D' position. Engine torque is transmitted from the torque converter turbine shaft to ring gear 1 of the single web planetary gear train and the outer plate carrier of clutch 'E'.
Ring gear 1 drives the planetary gears which rotate around sunwheel 1. This drives the planetary gear carrier 1 and also the outer plate carrier of clutch 'A' and the inner plate carrier of clutch 'B'.
When clutch 'A' is engaged, sunwheel 3 in the double web planetary gear train is driven and meshes with the short planetary gears.
The double web planetary gear carrier is driven via clutch 'E' which is engaged. The long planetary gears, which are also meshed with the short planetary gears, and the double web planetary gear carrier, drive ring gear 2 in the direction of engine rotation.
NOTE:
Refer to 'Shift Elements' illustration for key
Power Flow 5th Gear
The gear selector lever and the manual selector spool valve are in the 'D' position. Engine torque is transmitted from the torque converter turbine shaft to ring gear 1 of the single web planetary gear train and the outer plate carrier of clutch 'E'.
Ring gear 1 drives the planetary gears which rotate around sunwheel 1. This drives the planetary gear carrier 1 and also the outer plate carrier of clutch 'A' and the inner plate carrier of clutch 'B'.
When clutch 'A' is engaged, sunwheel 3 in the double web planetary gear train is driven and meshes with the short planetary gears.
The long planetary gears, which are also meshed with the short planetary gears, and the double web planetary gear carrier, drive ring gear 2 in the direction of engine rotation.
NOTE:
Refer to 'Shift Elements' illustration for key
Power Flow 6th Gear
The gear selector lever and the manual selector spool valve are in the 'D' position. Engine torque is transmitted from the torque converter turbine shaft to ring gear 1 of the single web planetary gear train and the outer plate carrier of clutch 'E'.
Clutches 'A' and 'B' are released, removing the effect of the single web planetary gear train.
Clutch brake 'C' is applied which locks sunwheel 2 to the transmission housing.
Clutch 'E' is engaged and drives the double web planetary gear carrier. This causes the long planetary gears to rotate around the fixed sunwheel 2 and transmit drive to ring gear 2 which is driven in the direction of engine rotation.
NOTE:
Refer to 'Shift Elements' illustration for key
Power Flow Reverse Gear
The gear selector lever and the manual selector spool valve are in the 'R' position. Engine torque is transmitted from the torque converter turbine shaft to ring gear 1 of the single web planetary gear train and the outer plate carrier of clutch 'E'.
Ring gear 1 drives the planetary gears of the single web planetary gear train which rotate around the fixed sunwheel 1. This transmits the drive to the single web planetary gear carrier, the outer plate carrier of clutch 'A' and the inner plate carrier of clutch 'B'.
With clutch 'B' applied, sunwheel 2 in the double web planetary gear train is driven and meshes with the long planetary gears.
The double web planetary gear carrier is locked to the transmission housing by brake clutch 'D'. This allows ring gear 2 to be driven in the opposite direction to engine rotation by the long planetary gears.
NOTE:
Refer to 'Shift Elements' illustration for key
SELECTOR POSITION SWITCH
The Mechatronic valve block contains a position switch which is mechanically connected to the selector spool valve. The selector spool valve is connected by a selector shaft to the selector lever via a 'Bowden' selector cable.
The signals from the position switch are used by the TCM to determine the P, R, N or D selection made by the driver.
FLUID COOLING
The transmission fluid cooler is an integral part of the engine cooling radiator. The transmission is connected to the fluid cooler via flexible hoses and metal pipes.
NOTE:
4.0L V6 Petrol shown, 4.4L V8 and TdV6 similar
The transmission cooler is integrated into the left hand end tank of the engine cooling radiator. The transmission fluid is cooled by the temperature differential between the transmission fluid and the engine coolant and also by airflow over cooling fins on the end tank.
Fluid is supplied from the transmission fluid pump into the lower connection of the cooler. After passing through the cooler, the fluid passes out of the upper connection and is returned to transmission fluid pan.
GEAR SELECTOR LEVER ASSEMBLY
The gear selector lever assembly is located in a central position on the transmission tunnel, between the front driver and passenger seats and is secured to the transmission tunnel closure plate. The selector lever comprises a moulded plastic housing which provides for the location of the selector components.
The lever is connected to a crosspiece which allows for the selection of P, R, N, D in a forward or backward direction and selection between automatic and manual/sport mode in a left/right transverse direction.
When manual/sport mode is selected the lever can be moved in a forward or backward direction to select + or - for manual (CommandShift) operation. If left in Sport mode all gear changes are performed automatically.
If Manual (CommandShift) mode is selected, all gear changes are based on inputs received by the TCM from the manual +/- hall effect sensors located on the PCB.
The selector lever mechanism houses the following components:
- Electronic Printed Circuit Board (PCB)
- Shift Interlock solenoid
- Park and Neutral locking levers.
There are four selector lever positions and two additional positions for manual/sport operation:
- P (Park) - Prevents the vehicle from moving by locking the transmission
- R (Reverse) - Select only when the vehicle is stationary and the engine is at idle
- N (Neutral) - No torque transmitted to drive wheels
- D (Drive) - This position uses all six forward gears in high and low ranges
- M/S (Sport Mode) - This position uses all forward gears in 'D' but will upshift at higher engine speeds to improve acceleration
- + and - (Manual 'CommandShift' mode) - Movement of the selector lever in the +/- positions, when the lever is in the M/S position, will operate the transmission in manual (CommandShift) mode allowing the driver to manually select all six forward gears
The selector lever position is displayed to the driver on the selector position LED display and in the instrument cluster. In 'CommandShift' mode, if a gear is selected but the TCM logic prevents selection of that gear, the requested gear will be initially displayed. The TCM will engage the next allowed gear and then display that gear.
Sport/Manual +/- CommandShift Switch
The PCB contains the hall effect sensors to activate the sport/manual mode and also the sensors which provide the +/- signals. When the selector lever is moved to the manual/sport position, the lower magnet located in the selector lever is moved within proximity of the M/S hall effect sensor on the PCB. This provides the momentary signal which is received by the TCM, which in turn initiates sport mode.
When the lever is moved to the + or - position, the magnet is moved within proximity of one of the hall effect sensors positioned either side of the M/S hall effect sensor. When an input from either the + or - sensors is received, manual CommandShift mode will be initiated. In this position a spring will move the selector lever back to the centre position when released. To leave the CommandShift mode, return the lever to the 'D' position.
Selector Position LED Display
The P, R, N, D LED display is located on the right hand side of the selector lever and the M/S (MANUAL/SPORT) +/- LED display is located on the left hand side of the selector lever. Each LED display is connected via a separate harness to the selector lever position switch. When the lever is moved to the required position, the switch contact for that position is made and the LED is illuminated.
P, R, N, D Position Switch
The P, R, N, D position switch is located within the Mechatronic valve block in the transmission. The switch is operated by movement of the selector lever to the P, R, N or D positions via the Bowden cable which is connected between the selector lever and the transmission selector shaft.
The switch is electrically connected to the TCM which outputs a common power supply to each of the four switch contacts. This power supply is also used by the two speed sensors and the fluid temperature sensor. Each of the four switch contacts have a separate feed input to the TCM which can detect which selector lever position has been selected.
Shift Interlock Solenoid
The shift interlock solenoid is located on the side of the selector lever assembly. The solenoid operates two locking levers which engage in the lower lever and lock it in the Park (P) and Neutral (N) positions. When the ignition is on or the engine is running, the solenoid is de-energized and prevents the lever from moving.
When energized, by the depression of the footbrake, the solenoid is energized and the selector lever may be moved from the P position. If the selector lever is left in the N position for more than 800m/s the solenoid will be energized and the selector lever will become locked in the N position. To move the selector lever from the N position in this condition the footbrake must be applied. This prevents the selector lever from being moved to the 'D' or 'R' position unintentionally and the application of the brakes also prevents the vehicle 'creeping' when the gear is engaged.
Movement of the selector lever from the 'P' or 'N' positions is also prevented if the TCM senses the engine speed is above 2500 rev/min, even if the brake pedal is depressed.
In the event of an electrical failure of the vehicle or failure of the interlock solenoid or its associated wiring, it is possible to move the selector lever from the Park 'P' position by removing the coin tray on left hand drive vehicles or the trim panel behind the park brake switch on right hand drive vehicles and lifting the white colored tab on the rear of the selector lever assembly. Whilst holding the tab in this position move the selector lever from the 'P' position.
The selector lever will also be locked in the N position during the transfer box changing range from high to low or vice versa.
Selector Cable
A selector cable is used as a mechanical connection between the selector lever and the transmission. The cable is a Bowden type cable which is connected to the selector lever. Movement of the lever in the P, R, N or D positions moves the cable. Movement of the cable is prevented when the selector lever is in the Manual/Sport position.
The cable is passed through a sealing grommet in the floorpan and is attached to a bracket on the transmission. The inner cable is connected to a lever which is positively attached to the transmission selector shaft.
Movement of the selector lever in the P, R, N or D positions moves the inner cable which in turn moves the lever. The lever transforms the linear movement of the cable into rotary movement of the selector shaft. The rotation of the shaft moves the position switch located within the Mechatronic valve block and also moves the manual spool valve to the applicable position.
Inputs and Outputs
Connector C2658
The following table shows the connector pin details for the connector on the selector lever assembly.
INSTRUMENT CLUSTER
The instrument cluster is connected to the TCM via the high speed CAN bus. Transmission status is transmitted by the TCM and displayed to the driver in one of two displays in the instrument cluster. For additional information, refer to Instrument Cluster
Malfunction Indicator Lamp (MIL)
The MIL is located in the tachometer in the instrument cluster. Transmission related faults which may affect the vehicle emissions output will illuminate the MIL.
The MIL is illuminated by the ECM on receipt of a relevant fault message from the TCM on the high speed CAN. The nature of the fault can be diagnosed using T4 which reads the fault codes stored in the TCM memory.
Transmission Status Display
The transmission status display is located in a Liquid Crystal Display (LCD) within the speedometer housing. The LCD shows the selector lever position and the selected transmission mode. When the selector lever is in the manual CommandShift position, the selector lever position display will show the selected gear ratio.
The following table shows the displays and their descriptions.
Message Centre Display
The message centre is located in the lower centre of the instrument cluster. The message centre is a LCD to relay vehicle status and operating information to the driver. The message centre can display messages relating to a number of the vehicle systems. The following list shows the possible transmission related messages:
- TRANSMISSION FAULT LIMITED GEARS AVAILABLE
- TRANSMISSION FAULT AND OVERHEAT
- TRANSMISSION FAULT
- TRANSMISSION OVERHEAT
TRANSMISSION CONTROL MODULE (TCM)
The TCM is an integral part of the Mechatronic valve block which is located at the bottom of the transmission, behind the fluid pan. The TCM is the main controlling component of the transmission.
The TCM processes signals from the transmission speed and temperature sensors, engine control module and other vehicle systems. From the received signal inputs and pre-programmed data, the module calculates the correct gear, torque converter clutch setting and optimum pressure settings for gear shift and lock-up clutch control.
The TCM outputs signals to control the shift control solenoid valve and the Electronic Pressure Regulator Solenoids (EPRS) to control the hydraulic operation of the transmission.
The ECM supplies the engine management data on the high speed CAN bus system. The TCM requires engine data to efficiently control the transmission operation, for example; flywheel torque, engine speed, accelerator pedal angle, engine temperature etc.
The steering angle sensor and the ABS module also supply data to the TCM on the high speed CAN bus system. The TCM uses data from these systems to suspend gear changes when the vehicle is cornering and/or the ABS module is controlling braking or traction control.
The selector lever is connected to the automatic transmission and the position switch in the transmission by a Bowden cable. Movement of the selector lever moves the position switch via the Bowden cable and the switch position informs the TCM of the selected position. The sport/manual +/- CommandShift switch passes manual/sport selections to the TCM. An additional switch provides a selector lever in park position signal. Once the selector lever position is confirmed, the TCM outputs appropriate information which is received by the instrument cluster to display the gear selection information in the message centre.
The Mechatronic valve block also contains the speed and temperature sensors. These are integral with the Mechatronic valve block and cannot be serviced individually. The speed sensors measure the transmission input and output speeds and pass signals to the TCM. The fluid temperature sensor is also located in the valve block and measures the fluid temperature of the transmission fluid in the fluid pan.
The TCM is connected to the starter relay coil. When the selector lever is in PARK or NEUTRAL, the module provides a ground for the coil allowing the starter relay to be energized and allow starter motor operation. If the selector lever is in any other position, the module will not provide the ground preventing starter motor operation.